Problem: At Academic Academy, to pass an algebra test you must score at least $80\%$. If there are 35 problems on the test, what is the greatest number you can miss and still pass?
Explanation: If you must score at least $80 \%$, then you cannot miss more than $20 \% = 1/5$ of the problems. $1/5$ of $35$ is equal to $7$, so you can miss at most $\boxed{7}$ problems and still pass.